Calcium carbonate nodule


New member
Dec 4, 2014
San Diego CA
pool and spa combo spa has calcium nodules all over in spa they are little . pool and spa got refinished about 1 year ago. the ph has been good 1or2 times ph was at 8. hardness in water is at 450 . is there something that i have done our company that refinished the pool and spa


Mod Squad
LifeTime Supporter
TFP Expert
May 19, 2010
Tucson, AZ
:wave: Welcome to TFP!!!

Sounds like you were letting the pH stay too high for too long and now you have calcium scaling.
Who maintains the chemistry? How often?
How often are you testing? With what test kit?


LifeTime Supporter
TFP Expert
Jul 25, 2011
The spa may have calcium scaling issues as mentioned above, but it also could be a delamination/cracking problem where a white calcium nodule forms.
A pH of 8.0 does not normally or necessarily cause scaling. Are the nodules random or like very rough sandpaper?
If you could post a picture or two, and the complete water test results, it may help us to determine what the problem is.